The PGM or Portable Graymap format is part of a package of open source graphics programs called Netpbm. Other Netpbm formats include PPM (Portable Pixmap) and PBM (Portable Bitmap), also known under the collective name of PNM (Portable Anymap). A PGM file includes a grayscale image, can work on a UNIX platform, as well as on Windows or Mac OS X, and can render a scope of up to 255 grayscale colors.
The APNG format is also known as "animated PNG" and is made up of a series of PNG files of the same size that are connected as an animation. APNG files are similar in function with GIFs, but they support better quality images and transparency.
The quick and simple way to handle your files is to get a quality piece of software, such as reaConverter. Although it is fast, this software is extremely efficient in managing a wide range of conversions. As you will soon realize, reaConverter will help you avoid spending countless hours trying to figure out how to convert PGMs. But at the same time, it will allow you to apply a wide range of editing options.
Start reaConverter and load all the .pgm files you intend to convert into .apng because, as opposed to most free online converters, reaConverter supports batch conversion. So you can save the time and energy you would lose with doing repetitive operations.
Select PGMs from a folder or by drag-and-dropping them directly into the reaConverter window.
Go to the Saving options tab and decide where you want to save new .apng files. You can also spend a few more moments to apply additional editing to the images prepared for conversion.
Then pick the APNG as output format. To help you do this, a series of buttons is conveniently placed at the bottom of the reaConverter window, so you can simply press on the one you need or click Plus button to add new options.
Then simply press the Start button and your conversion will begin in no time!Try Free Trial Version